Character reader utilizing stroke and cavity detection for recognition of characters



DeC- 6, 1956 J. M. BA|LEY, JR.. ETAL 3,290,650

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19 Sheets-Sheet 3 J. M. BAILEY, JR., ETAL Dec. 6, 1966 CHARACTER READER UTILIZING STROKE AND OAVITY DETECTION FOR RECOGNITION OE CHARACTERS Filed May 13, 1963 Dec. 6, 1966 J. M. BAILEY, JR. ETAL 3,290,650

CHARACTER READER UTILIZING TROKE AND CAVITY DETECTION FOR RECOGNITION OF CHARACTERS 19 Sheets-Sheet 4 Filed May 13, 1965 Dec. 6, 1966 J. M. BAILEY, JR.. ETAL 3,290,550

CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION OF CHARACTERS Filed May 13, 1965 19 Sheets-Sheet 5 .1. M. BMLEY. JR.. ETAL 3,290,650 CHARACTER READER UTILIZING STROKE AND CAVITY Decf. 6, 1966 DETEOTION FOR RECOGNITION OF lOHARAOTERS 19 Sheets-Sheet 6 Filed May 13, 1963 N .Nm MEN mb. n@ 2. i Li w w SPGM @u S www2 u m. mwwwvwwww N w\w A mw S k .N w Sj k Qu QS QN RN www. NL. Qmxwmn y R S www www mw A: www SQ N Q S n Q mw Y O v m. w w NNN v w NNN H www@ SQ@ SQ Stumm@ w xwk Q3 www Sui NR w Dec. 6, 1966 1. M. BAILEY. JR., ETAL 3,290,550

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CHARACTER EADER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION OF CHARACTERS Filed May l5, 1965 19 Sheets-Sheet 8 fOr/160 J. M. BAILEY, JR., ETAL. 3,290,650 CHARACTER READER UTILIZING STROKE AND CAVITY Dec. 6, 1966 DETECTION FOR RECOGNITION OF CHARACTERS 19 Sheets-Sheet 9 Filed May 13, 1963 USGM.

Dec. 6, 1966 J. M. BAILEY, JR., ETAI. 3,290,650

CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION 0F CHARACTERS Filed May l5, 1963 19 Sheets-Sheet 1D Dec. 6, 1966 Filed May 13, 1965 J. M. BAILEY, JR., ETAL CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION OF CHARACTERS 19 Sheets-Sheet 1l (z/ 5000 m 000/ 0000 0000 (0 500 0, 7 00W /000 0000 0000 001000000 0 f3) 00/ PZ 7 00W 0/00 0000 0000 000000000 0 f4) 000 037 70000 0/00 0000 0000 000000000 0 /0/ 50s 047 70000 0/00 0000 0000 000000000 0 /0 000 0,7 70000 0/00 0000 0000 000000000 0 (7) 500 067 7000/ 0/00 0000 0000 00000000 0 Z0) .500 070 0000 00/0 0000 0000 000000000 0 (7) 507 05 7 70000 00/0 0000 0000 500000000 0 (/0 007 097 70000 00/0 0000 0000 000000000 c (0) 007 00 7 70000 00/0 0000 0000 00000000 0 [0; 000 (0) 000] 00000 00 000A/ 007 (0) 00/0 (/0/ 000 g, 700000) 70000/ 00/0 000D 0000 000000 000 0 (/0) 00/0 0;, (00000) .l0/0 00/0 0000 0 000 $000000 0 (/7/ 00/0 02, 7 70000 00 /0 0000 0000 00000000 0 (/0) 000 00 700000) .0A/0 00/0 0000 0000 000000000 c (0) 0000 ,15, 7/00/0y00) .0A/0 00/0 0000 0000 500000010 0 (Z0) /57' 0000000 04/0 00/0 0000 0000 000000000 0 (2f) 2' iff/fm2 000 00/0 0000 00010 00 000005 100000000 007/000 Jaz/0f /40/0/ rfa/'000 J. M. BAILEY, JR., ETAL 3,290,650 CHARACTER READER UTILIZING STROKE AND CAVITY Dec. 6, 1966 DETECTION FOR RECOGNITION OF CHARACTERS 19 Sheets-Sheet l2 Filed May 13, 1965 J. M. BAILEY. JR., ETAL 3,290,650 CHARACTER READER UTILIZING STROKE AND CAVITY Dec. 6, 1966 DETECTION FOR RECOGNITION OF CHARACTERS Filed May 13, 1965 J. M. BAILEY. JR., ETAL 3,290,650 CHARACTER READER UTILIZING STROKE AND CAVITY Dec. 6, 1966 DETECTION FOR RECOGNITION OF CHARACTERS 19 Sheets-Sheet 14 Filed May 13, 1965 fia f i557... i ,w M V 5 il o n o F i an 4 w. WM n 0 n f M 5 .M 4 i i i u f7 1W4M m W 0 F M .f i c v 46h/wey DCC- 6, 1966 J. M. BAILEY, JR., ETAL 3,290,650

CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION OF CHARACTERS Filed May l5, 1963 19 Sheets-Sheet 16 M. BAILEY, JR. ETAL 3,290,650 CHARACTER READER UTILIZING Filed May 13, 1965 Dec. 6, 1966 TROKE AND CAvTY DETECTION FOR RECOGNITION OF CHARACTERS 19 Sheets-Sheet 17 Dec. 6, 1966 J. MQ BAILEY, JR., l-:TAL 3,290,650

CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION OF CHARACTERS Filed May 13, 1965 19 Sheetsheet 18 @7221.4 7PM# 745/5- f///l/A/ffi/'f 25 ZFK iJN O :fm2/c) L. I X O O O l l O F O I 0 O fra/fray Dec. 6, 1966 J. M. BAILEY, JR ETL CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION OF' CHARACTERS Filed May 13, 1965 mm/ ffirafff 19 Sheets-Sheet 19 BY gok ifm/Way United States Patent O f CHARACTER READER UTILIZING STROKE AND CAVITY DETECTION FOR RECOGNITION F CHARACTERS John M. Bailey, Jr., Barrington, Robert L. Adams, Haddonlield, and Julius Agin, Cherry Hill, NJ., assignors to Radio Corporation of America, a corporation of Delaware Filed May 13, 1963, Ser. No. 279,842 12 Claims. (Cl. S40-146.3)

Table 0f Contents Topics Col. Introduction l Description of Drawings 2 General Description of Character Reader 3 Character Scanning 4 Character Features 4 Stroke Features 5 Cavity Features 6 Width Features 7 Additional Objects 7 Feature Recognition Circuits 7 General Description 7 Width Feature Detectors g Stroke Feature Detectors' g Cavity Feature `Detectors 9 Abbreviations 9 Detailed Description of Feature Recognition Circuits 10 Character Control, etc. 1() Stroke Feature Detectors 13 Pulse Analyzer 13 Long Vertical Stroke Position Detector 15 Stroke Tracker Control 16 Stroke Counter and Tracker 17 Stroke Decoders 18 Stroke Direction Analyzers 20 Operation of Stroke Feature Detectors 21 Stroke Direction Analyzer Operation 26 Cavity Feature Detectors 27 Top Cavity Detector 27 Operation of Top Cavity Detector a 29 Bottom Cavity Detector 31 Operation of Bo-ttom Cavity Detector 32 Feature Output Buier Register and Control 34 General Description 34 Feature Output Buffer Register Control 35 Feature Output Buffer Register 35 Operation of Feature Output Buffer Register 36 Character Determining Circuit 37 General Description 37 Detailed Description 38 Operation 40 Summation 41 INTRODUCTION l ments produced by a computer-operated printer and thereafter returned to the character reader-computer com- 3,2%,656 Patented Dec. 6, 1966 ICC bination. Such character readers generally contain relatively simple recognition systems capable of reading numeric characters only. Furthermore, such character readers usually are not capable of reading characters from fonts differing from the type in the printer for which the character reader was designed.

For maximum utility, a character reader should be capable of reading alpha-numeric characters (i.e., both alphabetic and numeric) which are printed on original input documents by various makes of printers. Furthermore, the character reader should also be capable of reading characters from different fonts rather than requiring a standardized font for all the equipments supplying the source documents to the character reader.

Accordingly, it is an object of this invention to provide a new and improved character reader capable of reading alpha-numeric characters.

It is another object of this invention to provide a new and improved character reader capable of reading alphanumeric characters printed on original input documents.

It is another object of this invention to provide a new and improved character reader which is programmable to read alpha-numeric characters from a variety of different fonts.

A character reader in accordance with the invention utilizes the diiferent topographical features exhibited by different alpha-numeric characters to differentiate one character from another. The major topographical features relied upon are stroke features and cavity features. The strokes of a character are the different portions into which the outline trace of the character may be divided. The cavities of a character are the partially enclosed areas formed at the top and/ or bottom of some characters by portions of the outline trace of the character.

In an embodiment of the invention, alpha-numeric characters printed on a document are scanned successively by a plurality of vertical scans to derive video signals representing the features of the characters. The video signals are analyzed to derive the stroke and cavity' features of the characters. The stroke features detected from the video signals include the number of strokes occurring in a character as well as their beginning, ending, direction, and relative positioning in a character. The cavity feature detected includes the occurrence and size of the cavities formed at the top and/or bottom of some characters (such as the top cavity in a U and the top and bottom cavities in an M). Additional cavity features detected are a comparison of the top-to-bottom cavity sizes, and the squareness of the top and bottom left corners of the characters. Finally, an additional feature, the width of the characters is also detected.

The feature signals derived from each character are stored pending completion `of the scanning lof the entire character and are then compa-red against a memory of stored features to ascertain the identity -of the characters. Upon identification, the character reader produces a coded output signal representing the character for further processing by a computer.

The n-ovel features which are considered to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both to its organization and method of operation, as well as to additional objects and advantages thereof, will best be understood from the following description when read in conjunction with the accompanying drawings in which:

FIGURE l is a `schematic block diagram of a character reader embodying the invention;

FIGURE 2, comprising FIGURES 2a, 2b, 2c and 2d,

individual characters by the character reader in FIG- URE 1; 

2. IN A CHARACTER READER FOR READING CHARACTERS FROM A DOCUMENT, DIFFERENT ONES OF SAID CHARACTERS BEING FORMED OF DIFFERENT OUTLINE TRACES ON SAID DOCUMENT, THE OUTLINE TRACES OF SAID CHARACTERS EXHIBITING A PLURALITY OF TOPOGRAPHICAL FEATURES INCLUDING STROKES, SAID CHARACTER READER INCLUDING MEANS FOR SCANNING SUCCESSIVE ONES OF SAID CHARACTERS BY A PLURALITY OF SCANS TO DERIVE VIDEO SIGNALS REPRESENTING THE TOPOGRAPHY OF SAID CHARACTERS, THE COMBINATION COMPRISING, MEANS FOR DETECTING PULSES IN SAID VIDEO SIGNALS TO DETECT STROKES IN A CHARACTER, MEANS FOR COMPARING PULSES IN SUCCESSIVE SCANS OF A CHARACTER TO GENERATE STROKE INFORMATION SIGNALS FOR EACH STROKE DETECTED IN SAID CHARACTER, A PLURALITY OF STROKE ANALYZING CIRCUITS, ONE FOR EACH STROKE IN A CHARACTER, FOR ANALYZING SAID STROKE INFORMATION SIGNALS, A STROKE TRACKER HAVING A PLURALITY OF POSITIONS WITH EACH CONTAINING A DIFFERENTLY CODED SIGNAL FOR TAGGING EACH DETECTED STROKE WITH A DIFFERENT LABEL, MEANS FOR SUCCESSIVELY POSITIONING EACH OF SAID CODED SIGNALS INTO A PRESCRIBED POSITION IN SAID STROKE TRACKER ON EVERY SCAN TO SIGNAL THE SUCCESSIVE REDETECTIONS OF THE STROKES CORRESPONDING TO SAID CODED SIGNALS SO AS TO TRACK EACH OF SAID DETECTED STROKES FORM SCAN TO SCAN, A PLURALITY OF GATES, EACH ONE COUPLED TO A DIFFERENT STROKE ANLYZING CIRCUIT, FOR COUPLING SAID STROKE INFORMATION SIGNALS TO SAID STROKE ANALYZING CIRCUITS, EACH OF SAID GATES BEING ACTIVATED BY A DIFFERENT ONE OF SAID CODED SIGNALS, AND MEANS FOR APPLYING EACH SUCCESSIVE CODED SIGNALS IN SAID PRESCRIBED POSITION TO ALL OF SAID GATES TO PASS THE STROKE INFORMATION SIGNALS FROM A DETECTED STROKE INTO ITS CORRESPONDING STROKE ANALYZING CIRCUIT. 